1. Field of the Invention
The present invention relates to a process for preparing a shaped carrier which contains titanium oxide as the primary component. The carriers of this invention are suitable for use as catalyst supports.
2. Description of the Prior Art
Typically, solid catalysts are used in a supported form prepared by depositing the catalytic component on a carrier having the desired shape and diameter or in an unsupported form by forming the catalytic component into the desired shape and diameter. The solid catalysts prepared by either method can be used in either a fixed bed system or in a moving bed system. In either case, it is necessary for the catalyst to have enough strength for use in an industrial operation. When the catalyst is not strong enough, the catalyst disintegrates while being packed into the reactor; or becomes powdered or crushed by gas pressure or heat shock during the reaction to cause clogging in the reactor. In either case, the catalyst is not suitable for practical use.
Titanium oxide has certain desirable characteristics as a catalyst carrier or as a catalyst itself. However, it is difficult to obtain a shaped product having the desired mechanical strength. For example, in order to prepared a shaped product of titanium oxide suitable for use as a catalyst carrier, it is necessary to mold fine powdery titanium dioxide under compression produced by an extrusion molding machine, a tableting machine or a rolling granulator, or in the alternative, to shape it by agglomeration with water or a suitable binder.
With either technique, it is difficult to achieve enough agglomeration and difficult to prepare a shaped product having sufficient strength. On the other hand, it is possible to prepare a shaped product having a high degree of hardness and heat shock resistance by sintering titanium dioxide at temperatures above 1000.degree. C. However, the resulting sintered product has a high density, a low specific surface area, low porosity and is not suitable as a catalyst carrier.
There is then, a need for a process capable of preparing a shaped titanium oxide product which is suitable as a catalyst carrier.